<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div{
            width: 800px;
            margin: 0 auto;
        }
    </style>
</head>
<body>
    <div>
        <a href="./mycode/1-1/firstdemo.html">1-1 第一节课 firstdeom</a>
    </div>
</body>
</html>